1. Field of the Invention
The present invention belongs to the technical field in which processing is performed for a semiconductor wafer and a glass substrate used in a liquid crystal display, for example, by utilizing the photolithography technology. The invention particularly relates to a coating apparatus for applying a coating solution such as a resist solution or the like onto, for example, a semiconductor wafer and a glass substrate.
2. Description of the Related Art
In a process for fabricating a liquid crystal display device, a series of processing in which a circuit pattern or the like is reduced and exposed and transferred to a photo resist, and developing processing is performed for the same is carried out by using the photolithography technology as used in the semiconductor fabricating process in order to form an ITO thin film, an electrode pattern and the like, for example, on a glass substrate.
The above series of processing is performed by a coating and developing processing system with the configuration in which a cleaning apparatus, an adhesion processing apparatus, a cooling processing apparatus, a resist coating apparatus, a heating processing apparatus, a developing apparatus and the like are disposed along a transfer path on which a transfer device for transferring, for example, a glass substrate can travel. In the coating and developing processing system as above, after a glass substrate is cleaned in the cleaning apparatus, hydrophobic processing is performed for the glass substrate in the adhesion processing apparatus. Subsequently after the glass substrate is cooled in the cooling processing apparatus, coating of a photo resist film is formed thereon. Thereafter, the photo resist film is heated in the heating processing apparatus, thereby performing pre-bake processing, and thereafter it is cooled. A predetermined pattern is exposed in an aligner connected with the system. After a developing solution is applied to the glass substrate after exposure in the developing apparatus, thereby performing developing processing, the developing solution is cleaned therefrom by means of a rinse solution, and post-baking processing is performed, thus completing a series of process.
In the aforementioned resist coating apparatus, a spin coat method, in which a spin chuck is rotated with a glass substrate being placed on, for example, a spin chuck and a resist solution is supplied to the center of rotation, is used. However, when the resist solution is applied by such a spin coat method, the disadvantage, in which a considerable amount of resist solution supplied onto the glass substrate is shaken off to the outside of the glass substrate by centrifugal force and is wasted, arises.
The inventors of the present invention propose the art of applying a resist solution only to the area requiring it as much as possible by scan-moving a nozzle in a tapering form for discharging the resist solution over the top surface of a glass substrate to eliminate the waste of the resist solution.
However, the nozzle with the above configuration has the disadvantage of taking a very long time to apply the resist solution onto the entire surface of the glass substrate since the scanning pitch of the nozzle is small.
Especially when the viscosity of a resist solution is high, or when the contact angle of a glass substrate top surface is large, the spread of the resist solution on the glass substrate top surface becomes small, and therefore the scanning pitch of the nozzle needs to be made smaller, thus taking a longer time to perform coating processing of the resist solution.
Further, if a long time is taken to perform coating processing as above, the drying time of the resist solution at the spot to which it is initially applied to the glass substrate and the drying time of the resist solution at the spot to which it is finally applied considerably differ. Thus the disadvantage of losing uniformity of the film thickness arises.
It can be considered, for example, to increase a radius of a discharge aperture provided at a tip end of the nozzle, but if the radius of the discharge aperture is increased, the disadvantage arises that the resist solution cannot be held inside the nozzle and drops therefrom when the supply of the resist solution from the nozzle is stopped.
An object of the present invention is to provide a coating apparatus, with which the disadvantage of dropping a coating solution or the like as above does not occur, the waste of the coating solution is eliminated, and the time taken to perform coating processing can be reduced.
In order to attain the above object, according to the viewpoint of the present invention, a coating apparatus comprising a holding member for holding a substrate, a nozzle provided with a plurality of discharge apertures in line for discharging a coating solution toward a top surface of the held substrate, and a scanning mechanism for scan-moving the aforesaid nozzle over the held substrate is provided.
According to the above configuration, the coating solution is discharged from the plurality of discharge apertures at the same time while, for example, the nozzle is scan-moved in the direction orthogonal to the arranging direction of the discharge apertures, thereby making it possible to apply the coating solution onto the substrate with approximately the width of the discharge apertures arranged in line relative to the scanning direction of the nozzle. Consequently, the waste of the coating solution is eliminated, and the time taken to perform coating processing can be reduced. Since it is not necessary to increase the radius of each discharge aperture, the coating solution does not drop.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.